3
Areas of heaviest use of PCBs; contaminated areas; continued use and accidental release; Areas of most recent widespread use of many OCPs (e.g., chlordane, dieldrin, HCHs); direct application, release Development and disturbance of former agricultural lands; post World War II and Silicon Valley boom in the 1960s Persistence in watershed soils and aquatic sediments due to chemical and physical stability; Continuing local, regional, and global impacts from cycling of contaminant residues through non-point source pollution pathways (i.e., runoff, atmospheric) Legacy contamination in urban environment Item #2